The National Grid has teamed up with E.ON to use surplus waste heat to power 100,000 new homes. The result is the world's largest multi-site waste heat recycling project. This has enabled the National Grid to cut its carbon emissions by 50% at its Isle of Grain Liquefied Natural Gas (LNG) facility, near London.

The project came about after National Grid realised that just 3km away from its Isle of Grain plant, E.ON was building a new power station that would need to dispose of 600 MWh of surplus heat into the River Medway every day.

By using this heat, Grain LNG has reduced its annual gas usage by 169mcubic metres and its carbon emissions by up to 300,000 tonnes per year. That's the equivalent to taking 60,000 cars off the road.

The company achieved this reduction by using ten large pumps to move up to 5m litres of water through twin pipes across 3km.

This was technically difficult as the pipelines had to run under a public highway, across marshland and around existing pipelines.

In addition, both business have different peak and slack periods, so the companies needed to engineer a system that could accommodate 0%-100% flows at either end.

But the project has not just achieved considerable carbon savings. It also delivers on the National Grid's commitment to the environment as less heated water is pumped into the River Medway, a Site of Special Scientific Interest. This benefits aquatic life as heat reduces oxygen and stimulates excessive algae growth.

Its engineering achievements on this project are also transferable to other power stations internationally.

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